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authorHung-ying Tyan <tyanh@chromium.org>2013-05-15 18:27:30 +0800
committerTom Rini <trini@ti.com>2013-06-26 10:13:24 -0400
commitf3424c554c572761f35b00988deb8ed35d1870e3 (patch)
treebd4d66a127bb045d1c4968fde86d3c25e1f0ddb1 /drivers/misc
parent78764a4e11dd40005ba2b36848de407070ccc1a7 (diff)
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cros: exynos: add SPI support for cros_ec
This patch adds SPI support for carrying out the cros_ec protocol. Signed-off-by: Hung-ying Tyan <tyanh@chromium.org> Signed-off-by: Randall Spangler <rspangler@chromium.org> Signed-off-by: Simon Glass <sjg@chromium.org> Acked-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/Makefile1
-rw-r--r--drivers/misc/cros_ec_spi.c161
2 files changed, 162 insertions, 0 deletions
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 51e59a6..0b1ef77 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -30,6 +30,7 @@ COBJS-$(CONFIG_DS4510) += ds4510.o
COBJS-$(CONFIG_CBMEM_CONSOLE) += cbmem_console.o
COBJS-$(CONFIG_CROS_EC) += cros_ec.o
COBJS-$(CONFIG_CROS_EC_I2C) += cros_ec_i2c.o
+COBJS-$(CONFIG_CROS_EC_SPI) += cros_ec_spi.o
COBJS-$(CONFIG_FSL_IIM) += fsl_iim.o
COBJS-$(CONFIG_GPIO_LED) += gpio_led.o
COBJS-$(CONFIG_FSL_MC9SDZ60) += mc9sdz60.o
diff --git a/drivers/misc/cros_ec_spi.c b/drivers/misc/cros_ec_spi.c
new file mode 100644
index 0000000..e15c833
--- /dev/null
+++ b/drivers/misc/cros_ec_spi.c
@@ -0,0 +1,161 @@
+/*
+ * Chromium OS cros_ec driver - SPI interface
+ *
+ * Copyright (c) 2012 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * The Matrix Keyboard Protocol driver handles talking to the keyboard
+ * controller chip. Mostly this is for keyboard functions, but some other
+ * things have slipped in, so we provide generic services to talk to the
+ * KBC.
+ */
+
+#include <common.h>
+#include <cros_ec.h>
+#include <spi.h>
+
+/**
+ * Send a command to a LPC CROS_EC device and return the reply.
+ *
+ * The device's internal input/output buffers are used.
+ *
+ * @param dev CROS_EC device
+ * @param cmd Command to send (EC_CMD_...)
+ * @param cmd_version Version of command to send (EC_VER_...)
+ * @param dout Output data (may be NULL If dout_len=0)
+ * @param dout_len Size of output data in bytes
+ * @param dinp Returns pointer to response data. This will be
+ * untouched unless we return a value > 0.
+ * @param din_len Maximum size of response in bytes
+ * @return number of bytes in response, or -1 on error
+ */
+int cros_ec_spi_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
+ const uint8_t *dout, int dout_len,
+ uint8_t **dinp, int din_len)
+{
+ int in_bytes = din_len + 4; /* status, length, checksum, trailer */
+ uint8_t *out;
+ uint8_t *p;
+ int csum, len;
+ int rv;
+
+ /*
+ * Sanity-check input size to make sure it plus transaction overhead
+ * fits in the internal device buffer.
+ */
+ if (in_bytes > sizeof(dev->din)) {
+ debug("%s: Cannot receive %d bytes\n", __func__, din_len);
+ return -1;
+ }
+
+ /* We represent message length as a byte */
+ if (dout_len > 0xff) {
+ debug("%s: Cannot send %d bytes\n", __func__, dout_len);
+ return -1;
+ }
+
+ /*
+ * Clear input buffer so we don't get false hits for MSG_HEADER
+ */
+ memset(dev->din, '\0', in_bytes);
+
+ if (spi_claim_bus(dev->spi)) {
+ debug("%s: Cannot claim SPI bus\n", __func__);
+ return -1;
+ }
+
+ out = dev->dout;
+ out[0] = cmd_version;
+ out[1] = cmd;
+ out[2] = (uint8_t)dout_len;
+ memcpy(out + 3, dout, dout_len);
+ csum = cros_ec_calc_checksum(out, 3)
+ + cros_ec_calc_checksum(dout, dout_len);
+ out[3 + dout_len] = (uint8_t)csum;
+
+ /*
+ * Send output data and receive input data starting such that the
+ * message body will be dword aligned.
+ */
+ p = dev->din + sizeof(int64_t) - 2;
+ len = dout_len + 4;
+ cros_ec_dump_data("out", cmd, out, len);
+ rv = spi_xfer(dev->spi, max(len, in_bytes) * 8, out, p,
+ SPI_XFER_BEGIN | SPI_XFER_END);
+
+ spi_release_bus(dev->spi);
+
+ if (rv) {
+ debug("%s: Cannot complete SPI transfer\n", __func__);
+ return -1;
+ }
+
+ len = min(p[1], din_len);
+ cros_ec_dump_data("in", -1, p, len + 3);
+
+ /* Response code is first byte of message */
+ if (p[0] != EC_RES_SUCCESS) {
+ printf("%s: Returned status %d\n", __func__, p[0]);
+ return -(int)(p[0]);
+ }
+
+ /* Check checksum */
+ csum = cros_ec_calc_checksum(p, len + 2);
+ if (csum != p[len + 2]) {
+ debug("%s: Invalid checksum rx %#02x, calced %#02x\n", __func__,
+ p[2 + len], csum);
+ return -1;
+ }
+
+ /* Anything else is the response data */
+ *dinp = p + 2;
+
+ return len;
+}
+
+int cros_ec_spi_decode_fdt(struct cros_ec_dev *dev, const void *blob)
+{
+ /* Decode interface-specific FDT params */
+ dev->max_frequency = fdtdec_get_int(blob, dev->node,
+ "spi-max-frequency", 500000);
+ dev->cs = fdtdec_get_int(blob, dev->node, "reg", 0);
+
+ return 0;
+}
+
+/**
+ * Initialize SPI protocol.
+ *
+ * @param dev CROS_EC device
+ * @param blob Device tree blob
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_spi_init(struct cros_ec_dev *dev, const void *blob)
+{
+ dev->spi = spi_setup_slave_fdt(blob, dev->parent_node,
+ dev->cs, dev->max_frequency, 0);
+ if (!dev->spi) {
+ debug("%s: Could not setup SPI slave\n", __func__);
+ return -1;
+ }
+
+ return 0;
+}